1. Field of Invention
The present invention relates generally to a three-dimensional (3D) model in a computer rendering environment and specifically to a method, apparatus, and system for automatic assignment of materials to a 3D computer aided design (CAD) model.
2. Description of Related Art
Computer rendering is a process used to generate images of 3D models. The goal is often an image of the model that looks like a photograph of the real object in the real world. This particular instance of rendering is called photorealistic rendering. Other instances of rendering include stylistic rendering for illustration purposes.
Computer generated imagery of 3D CAD models include a description of both the materials and lighting of the 3D model. The description of the materials includes how the light reflects in different directions as it strikes a specific part of the 3D CAD model.
CAD is the use of computer technology for computer aided drafting. CAD often involves more than just shapes. As in the manual drafting of technical and engineering drawings, the output of CAD must convey information, such as materials, processes, dimensions, and tolerances, according to application-specific conventions. CAD may be used to design curves and figures in two-dimensional (2D) space; or curves, surfaces, and solids in three-dimensional (3D) space.
CAD is an important industrial art extensively used in many applications, including automotive, shipbuilding, and aerospace industries, industrial and architectural design, prosthetics, and many more. CAD is also widely used to produce computer animation for special effects in movies, advertising, and technical manuals. The modern ubiquity and power of computers means that even perfume bottles and shampoo dispensers are designed using techniques unheard of by engineers of the 1960s. Because of its enormous economic importance, CAD has been a major driving force for research in computational geometry, computer graphics (both hardware and software), and discrete differential geometry.
CAD is mainly used for detailed engineering of 3D models and/or 2D drawings of physical components, but it is also used throughout the design and engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components. It can also be used to design objects.
A problem with the existing assignment of 3D CAD model materials is that a particular 3D CAD model can have tens or even hundreds of parts with different materials. Assigning materials to the particular 3D CAD model is a very time consuming and tedious task.
U.S. Pat. No. 5,140,672 to Suzuki is directed to a diagram generator having reference table which includes reproducing and name assigning units for expanding circuit from lower to higher level. An expansive circuit diagram information generator for use with computer aided design (CAD) systems is used to generate expansive circuit diagrams from a hierarchical circuit diagram. The expansion method makes the expanded circuit diagram more easily readable for its user. The circuit diagram generator consists of the following: an input for the hierarchical circuit diagram composed of high level circuits and low level circuit references; a reproducing unit to insert circuits into the lower level circuit references from a table of standard circuits; a name changing unit to make unique the names between the lower level circuit diagrams which the reproducing unit made identical by referencing two identical circuits from the standards table; and an interface symbol changing unit for replacing links between higher level circuit diagrams and lower level circuit diagrams with jump tags. Although Suzuki's system includes a name changing/assigning unit, Suzuki's name changing unit creates a unique name and does not standardize names such that a template could assign or change the material for each instance of a particular part name.